| Research Abstract |
To elucidate neural mechanism of sexual behavior and related humoral factors, we investigated (1) effects of electrical and chemical stimulation of the hypthalamus, tegmentum and central gray on sexual behavior (2) hypothalamic neuron activity during sexual behavior, (3) relationship between hypothalamic mechanism of feeding control and that of sexual behavior, and (4) changes in neuropeptides in cerebrospinal fluid during sexual behavior or after hypothalamic stimulation.
1. In male monkeys, electrical stimulation of the medial preoptic area, the dorsomedial nucleus of the hypothalamus, the ventral tegmental area, the substantia nigra, the nucleus reticularis mesencephali and the nucleus reticularis pontis oralis et caudalis elicited components of sexual behavior, such as touching and mounting. In female monkeys, the medial preoptic area, the ventromedial nucleus of the hypothalamus and the midbrain central gray were the effective area to evoked female sexual behavior, presenting. Na-glutamate injection into the area where electrical stimulation was effective did not elicit touching or mounting in the male monkey.
2. Activity of medial preoptic neuron of both male and female monkeys was related to sexual arousal, while increased neuron activities of the male dorsomedial hypothalamic nucleus and the female ventromedial hypothalamic nucleus was found to be synchronized to each mating act.
3. Electrical and chemical stimulation of the dorsomedial nucleus and the ventromedial nucleus of the hypothalamus suppressed execution of bar-press feeding task. Sexual behaviors were not elicited when the partner was put away from the stimulated monkey or replaced by submissive monkeys or humans. Similar stimulation elicited different behavioral responses in different environment.
4. Humoral factors which are involved in regulation of monkey sexual behavior remained to be investigated further in detail.
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